This application claims priority to Provisional Application No. 60/541,917 filed on Feb. 6, 2004, the entire content of which is hereby incorporated by reference thereto.
Flanging is the process used to roll the open end of the body on a typical 2-piece beverage or food can, in preparation for the filling operation. The flange material, basically perpendicular to the axial centerline of the can, is rolled to create a double seam with the lid after the can has been filled. The final width of the flange is critical in ensuring the seam has sealed the pressurized contents of the container properly.
The flange is dimensionally defined by the following criteria: (See FIGS. 1A, 1B and 1C)                Plug Diameter—the upper inside diameter of the can that must match precisely with the filler's equipment.        Under Flange Radius—the radius formed between the can body and the flange.        Flange Angle—the angle of the flange normal to the dome (stand) of the can.        Flange Width—the width of the flange from inside diameter to the flange outside diameter.        
Single stage, in-line flanging equipment on cascading, fixed-base and modular necking systems are known as are stand-alone flanger machines where no necking process is required. Flanging also takes place after conventional necking processes. Flanging on known equipment has been accomplished with two basic types of tooling.
1) Axial Spinheads—these assemblies, as shown in FIGS. 2A and 2B, typically consist of 3 or more free-spinning rollers whose axes are parallel to the centerline of the can body. The stationary can is driven axially into the assembly while the spinhead rotates. The rollers are profiled to create the flange matching given specifications and can be accomplished on a number of different neck diameters.
2) Radial Spinheads—the radial spinhead design typically incorporating 3 or 4 free-spinning rollers, was introduced in 1996 as an alternative to the axial system. The rollers in this assembly are positioned perpendicular to the axial centerline of the can body, with the stationary can and rotating spinhead concept remaining the same. This design has been provided on systems which are commercially available necking systems and available from Belvac Production Machinery, Inc. (Belvac®—located in Virginia) since 1996, with the exception of those producing a quad-neck or the like configuration.
The following process improvements were realized with the configuration of the nature depicted in FIGS. 3A and 3B. By way of example, the arrangement show in FIG. 3A is configured to have (merely by way of example) a theoretical plug diameter of 2.260″ and a roller radius of RO.0600″. On the other hand, the arrangement shown in FIG. 3B is configured for a different can neck size, and has (merely by way of example) a theoretical plug diameter of 2.160″ and a roller radius of RO.0600″. These arrangements produce the following advantages.                Reduced process loads        Minimized the amount of stretching of the final plug diameter        Minimized deformation of the neck profile        Greater control of flange angle, width, and factory finished can height (FFCH)        Produced a smaller under flange radius        
With both spinhead assembly designs, the final flange geometry is determined by the profile of the rollers. (See FIG. 4 for a typical geometry). No positive limit is used to control the size of the flange outside diameter. The best that can be expected with use of the radial spinheads, as far as flange width variation is concerned, is an amount equal to or slightly less than that of the incoming can final neck height variation.